Thermoplastic elastomers are polymeric compositions that are used in the manufacture of a wide variety of products ranging from shoe soles to stretch wrap films. Such films have numerous commercial applications. For example, U.S. Pat. No. 4,166,464 issued to Korpman on Sep. 4, 1979 discloses a laminated absorbent dressing incorporating an elastic backing film made from a blend including thermoplastic elastomers. U.S. Pat. No. 4,476,180 issued to Wnuk on Oct. 9, 1984 also discloses films incorporating thermoplastic elastomers.
A need has arisen, however, for a film that may be heat sealed to various substrates and subsequently peeled from the substrate with a low and relatively constant peel force. The ability to peel the film from the substrate through the application of a uniform relatively low peel force is especially important in the case where the film has been heat sealed to a substrate which forms, together with the film, a package, or multiple serially connected packages. In the case of serially connected packages, if excessive or non-uniform force is required to peel the film from the substrate, it is exceedingly difficult to open the individual packages and extract the packaged items in a controlled fashion either mechanically or manually. It is highly desirable that the film be transparent to allow visual inspection of the packaged articles and that the film possess sufficient antiblocking properties to prevent the packaged articles from adhering to the film when the film is peeled from the substrate. It is also highly desirable that the elastic properties of the film be sufficient to allow the serially connected compartments to be flexed or wound without damaging the integrity of the seal formed between the substrate and the film. Thus, the elastic properties of the film should be sufficient to resist the shear force created when the substrate is flexed or wound without separating from the substrate.